The present invention pertains to a card-cage audio visual signal control system with card ID assignment. Conventionally, the core of many audio/visual presentation systems has been made up of a collection of several different stand-alone products, each accomplishing a particular function. A better approach to managing signals is using a modular card-cage solution that permits distribution, switching, matrix switching, and signal conversion in one comprehensive rack-based system. A modular card-cage solution provides the following advantages over a collection of several different stand-alone products:    (1) Flexibility: A modular card-cage solution enables the user to adapt to changes quickly. For example, if a system requires a composite video switcher one day and an S-Video switcher the next, the user can just add another card.    (2) Expandability: To expand the capabilities of the existing modular card-cage signal management system, the user can simply add more cards. Once all of the card slots are filled in a single cage, the user can add an additional cage and loop the RS-232 control.    (3) Space reduction: By eliminating redundant elements, more can be accomplished in a smaller space, using one RS-232 connection and one power connector. This is crucial for portable systems and crowded racks.    (4) Training reduction: Once the user is familiar with operating and programming a few cards in the modular card-cage signal management system, the user will adapt quickly to new cards that are introduced.    (5) Future proofing: With the modular card-cage signal management system, the user can keep the cards for the signal formats that remain common in the industry, and switch out the ones that don't for newer cards developed to meet industry trends.